Such a remote control is known from DE 196 53 840 A1. There, a handheld transmitter for a remotely activated central locking system in motor vehicles is shown, having a housing, a transmitting means, an electronic control circuit for controlling the transmitting means, and a solar cell, which supplies electrical energy to the control circuit.
GB 2 396 046 A shows an alarm-code trailer with a housing of transparent plastic, inside which is arranged an incandescent bulb, which begins to shine in case of an alarm. Furthermore, two pushbutton switches are provided on the housing for activating and deactivating the alarm.
US 2003/0206128 A1 shows a universal remote control with a transparent acrylic housing, inside which is arranged an incandescent bulb. The bulb can be lit and an acoustical transmitter activated by a locator device.
DE 20 2005 015 165 U1 shows a remote controlled locking device for a motor vehicle, in which a keypad and a display of a touch screen are formed.
Remote controls for the control of electronic appliances, such as television sets, radios, video recorders, satellite receivers, DVD players, but also other household appliances such as lighting fixtures, roll-down shutters, garage doors and the like, are quite common today. They usually have a housing with battery compartment, a printed circuit board with electronic components, a keypad and a transmitting unit, such as an infrared transmitting diode. One of the pushbuttons is normally used for switching the remote control on and off. The other pushbuttons are each assigned one or more functions, so that when the button is pressed an encoded infrared signal is sent out to the appliance being controlled.
The problem with such remote controls is the large and unmanageable number of pushbuttons. Many remote controls have more than 40 buttons, whose functions the majority of users cannot take note of.
EP 1 185 922 B1 therefore proposes, to simplify the use of a multimedia system, a scrolled cross point navigation on a user interface, which requires a remote control with only a few buttons, by which all available functions can be called up on a monitor screen, such as a television receiver.
Instead of a keypad with individual mechanically activated pushbuttons, it has also been proposed to use a touch-sensitive keypad, generally known as a touch pad (see DE 199 08 406 A1, DE 100 13 444 A1, EP 0 813 743 B1) or also a so-called touch screen, i.e., a display device that is touch-sensitive at the same time (see U.S. Pat. No. 5,237,327, U.S. Pat. No. 5,353,016 or EP 0 946 918 B1).
Touch pads and touch screens are generally familiar and described, e.g., in WO 92/04724 A1 or DE 20 2007 001 624 U1. They work by various principles, including capacitive, resistive, optical or with sound waves (surface acoustic waves). These devices, subsumed as “touch-sensitive keypads” or “touch-sensitive control surfaces”, produce an electrical signal, which is generally coordinated distinctly with one or more places on their surface, which is touched by an object or a finger.
It is thus possible to replace the functions of a keypad with individual mechanical buttons by a touch-sensitive keypad by assigning definite functions to definite regions of the keypad.
In the aforementioned WO 92/04724, DE 199 08 406 A1, DE 100 13 444 A1 and U.S. Pat. No. 5,353,016, the keypad is transparent and consists, e.g., of a transparent glass plate.
The problem here, nonetheless, is that the user has to touch certain precisely predetermined areas in order to operate the remote control, which generally requires the user to look at the touch screen in order to touch the correct physical location for the desired function. This is difficult in darkened rooms, such as when watching television or showing a movie. There are also difficulties for persons with impaired vision, for example, if they are “far-sighted” (presbyopia) and require glasses for close-range vision, but not for the far range where the monitor screen is located.